Microcontrollers with MCS-51 architecture of Atmel are one of the first product with inbuilt Flash program memory. Such attitude of Atmel gained popularity of its products among embedded system designers and hobbyists. Built in flash memory reduced the overall cost of microcontrollers. As we know the main popularity of Atmel is gained by AVR microcontrollers where flash memory is used with self programming abilities. This step of Atmel organisation made other companies like Motorola, Philips, Texas Instruments to release flash microcontrollers.

All Atmel microcontrollers of family MCS-51 with flash memory are marked as “89”. This rule is followed by other manufacturers like Philips, Temic, SST, ISSI, just Winbond corporation marks them as W77 and W78.

Write cycles of AT89 family microcontroller flash are over 1000.

Reading AT89 microcontroller markings can give yo ua bunch of information like letter “C” (AT89C) says that chip is based on CMOS technology and parameters are similar to similar microcontrollers of other organisations like Intel 80C51 or Philips 87C52.

Marking AT89LV means that power supply level is reduced to 2.7V.

AT89S has ability to be in system programmed (ISP) using ISP interface.

AT89LS has ISP ability but also should be powered by voltage of 2.7V.

There are two types of cores of MCS-51 family:

• C51 – standard core with 128 bytes of RAM and 3 timers;

• C52 – modified core with 256 bytes of RAM and 3 timers.

Marking of C55 or C54 or C58 indicates the amount of program memory (flash) from 16 to 32 kbytes.

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This entry was posted on Friday, September 8th, 2006 at 11:10 am and is filed under MCS-51 family. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.